A trading system needs current market data, and there are two ways to get it. Polling means asking the data source "what's the price now?" on a repeating timer. Streaming means opening a persistent connection (a websocket) and having the source push updates the instant they change. The choice shapes how fresh your view of the market is.

The freshness gap

Polling every second means your data can be up to a second stale — and on a fast-moving option, a second-old quote is a wrong quote. Poll faster and you hammer rate limits and waste calls when nothing changed. Streaming eliminates the gap: you know the moment the price moves, with no timer lag and no wasted requests.

Why streaming wins for execution

Combined with an event loop, a streaming feed lets a system react the instant the market moves rather than on its next scheduled check. That's the difference between acting on a live tape and acting on a slightly-old snapshot — exactly where latency and slippage creep in for short-term trades.

Polling asks "what's the price?" and hopes it's still true. Streaming already knows it changed.

The resilience nuance

Streaming has a catch: connections drop. A robust system treats a stale or dead stream as a red flag — it knows the difference between "the price hasn't moved" and "I've stopped hearing about it," and refuses to trade on data it can't trust. Prioritizing a fresh streaming feed, with polling as a backstop and a staleness guard, is the kind of data hygiene a serious execution tool like NoVo is built around.